They wouldn't want to pay someone to run communities, the "thinking" work that moderators do.
They won't mind paying call-center-level employees/contractors to do the janitor work, the "unthinking" work, which is voluminous.
They only have to do it until more mods come on board.
And don't forget they already have a lot of mods from subs that didn't blackout at all, and likely some from subs that already reopened.
It will not be hard or too terribly expensive for them to keep things running well enough that the masses are placated.